If they’d lost, they’d be dead now: North Korean dictator Kim Jong-un meeting with the country’s women’s soccer team, which won the East Asia Cup. Photo: Getty

From the start of his presidency, Barack Obama made reducing the world’s stock of nuclear weapons a priority, but that vision is now in shambles.

Last week, we learned that North Korea is quietly expanding its uranium-enrichment capacity at the Yongbyon facility. Nuclear-watchdog analyses of satellite photos and other data show that while Pyongyang had 2,000 centrifuges there three years ago, it now has 4,000. This doubling of capacity will let the Kim regime build four enriched-uranium bombs a year.

Analysts believe that Pyongyang has built fewer than a dozen plutonium-based bombs since it first tested a crude device in 2006. Now, with the more efficient enriched-uranium path, its capacity to threaten its neighbors is growing by leaps and bounds.

Meanwhile, as the North Koreans turn from plutonium to enriched uranium, Iran is moving in the opposite direction.

The Wall Street Journal reported last week that, while the world has for years concentrated on the pace of Iran’s spinning centrifuges in secret enrichment sites like the Fordow facility, Tehran has quietly advanced plutonium production at its heavy-water plant in Arak — an alternate path that may allow it to build a bomb by next summer.

Testing plutonium-fueled bombs is how India and Pakistan went nuclear in the late 1990s, when they broke the five-superpower monopoly on nuclear weapons and ended a balance of power that had lasted for most of the second half of the 20th century.

Of course, Iran might just become “merely” a nuclear-ready power. The message will still be the same: We’re here, we’re nuclear, get used to it.

But it doesn’t end there.

As the world’s worst regime is set to further threaten East Asia, North Korea’s neighbors are unlikely to sit by and watch — especially when America is cutting naval budgets that once guaranteed their safety.

Japan, for one, has all the technology it needs to become a nuclear power. For all the deep historical trauma in the country of Hiroshima and Nagasaki, Tokyo may have no choice but to get its own bomb as the North Korean threat grows.

Ditto South Korea, Indonesia, et al.

And as the Mideast sectarian wars heat up, Saudi Arabia, its Gulf neighbors and other Sunni stalwarts like Turkey are unlikely to let Shiite Iran become the neighborhood’s only nuclear power.

As the club grows, going nuclear gets ever easier. Pakistan’s AQ Khan showed in the last decade how readily scientists can spread nuclear know-how.

What about Obama? In 2009, Obama told Czechs in a Prague speech that one of his top goals as president would be to “seek the peace and security of a world without nuclear weapons.” He then pursued nuclear-arms-reducing pacts with Russia with all the enthusiasm of a 1980s “no-nukes” campus activist.

Along the way, he angered those Czechs and other European allies, like Poland, as he scrapped missile-defense projects just to induce Moscow to sign those treaties.

But signing those pacts didn’t shift the world’s course — because this era’s nuclear story isn’t about the size of US and Russian arsenals.

And as he worked on his Moscow “reset,” Obama’s half-hearted attempts to reverse Pyongyang nuclear advances went nowhere. And he’s seen no progress on his declared goal of stopping Iran from getting the bomb, either.